\(P\) and \(Q\) are isomers of dicarboxylic acid \(\mathrm{C}_{4}\mathrm{H}_{4}\mathrm{O}_{4}\). Both decolorize \(\mathrm{Br}_{2}/\mathrm{H}_{2}\mathrm{O}\). On heating, \(\boldsymbol{P}\) forms the cyclic anhydride. Upon treatment with dilute alkaline \(\mathrm{KMnO}_{4}\), \(P\) as well as \(\boldsymbol{Q}\) could produce one or more than one from \(\boldsymbol{S}, \boldsymbol{T}\) and \(\boldsymbol{U}\). In the following reaction sequences \(V\) and \(W\) are, respectively \[ Q \xrightarrow[\Delta]{\mathrm{H}_{2} / \mathrm{Ni}} V \]

JEE Advanced · 2013 · 02 Jun 2013 · Paper 2 · General Organic Chemistry

P

and

Q

are isomers of dicarboxylic acid

C_{4} H_{4} O_{4}

. Both decolorize

Br_{2} / H_{2} O

. On heating,

P

forms the cyclic anhydride. Upon treatment with dilute alkaline

KMnO_{4}

P

as well as

Q

could produce one or more than one from

S, T

and

U

.

In the following reaction sequences

V

and

W

are, respectively

Q H_{2} / Ni Δ V

Answer: (A)

Q

is fumaric acid (trans-butenedioic acid). Hydrogenation with

H_{2} / Ni

reduces the double bond to give succinic acid. Heating succinic acid forms succinic anhydride (

V

).

Further heating/decarboxylation can lead to cyclic products. The reaction sequence produces the cyclic anhydride and a cyclic ketone (

W

JEE Advanced · 2013 · 02 Jun 2013 · Paper 2 · Single correct option